I am a current house flipper and looking to start converting into more passive investments and am really interested in the note investing concept. 

With high interest rates, you most often don't get cash flow and it can even be negative.

For the MTR option I calculated a rent price of $2,900 (on the lower side) and got a ROI of 12% but a negative CoC return.

This morning I was able to get a Veteran approved who had a bunch of credit issues, foreclosure 4 years ago, overdraft fees in his bank account, negative bank balance, high debt ratios and a whole host of other challenges.

Also, if you get a negative cleaning review, you can speak with your cleaners and talk about areas you can work to improve on to ensure success.  

Just remember: most negative reviews are written by problematic tenants.

So between those two your cashflow is negative now. 

I would let them know that you have documented proof that they screwed up, and if they won't waive the fees then you will make it your personal mission in life to leave a negative review (with proof) on any website that allows reviews. 

They have no concept of how to manage time... 

If after a year or two or ten or twenty you decide you want to sell or trade in this vehicle and invest in a new one, the profit you stand to make will most likely be $0 or in the negative.